exports.add = function(a,b){
    return a+b;
}
exports.reduce = function(a,b){
    return a-b;
}
exports.division = function(a,b){
    return a/b;
}
exports.mult = function(a,b){
    return a*b;
}
exports.format = function(str,len){
    var result = str;
    for(let i = 0; i<len-str.length;i++){
        result = "0"+result;
    }
    return result;
}